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EHCI: add delay to bus_resume before accessing ports
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This patch (as870) adds a delay to ehci-hcd's bus_resume routine.
Apparently there are controllers and/or BIOSes out there which need
such a delay to get the ports back into their correct state.  This
fixes Bugzilla #8190.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored and Greg Kroah-Hartman committed Apr 27, 2007
1 parent eaafbc3 commit e198a31
Showing 1 changed file with 4 additions and 0 deletions.
4 changes: 4 additions & 0 deletions drivers/usb/host/ehci-hub.c
Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,10 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
/* restore CMD_RUN, framelist size, and irq threshold */
ehci_writel(ehci, ehci->command, &ehci->regs->command);

/* Some controller/firmware combinations need a delay during which
* they set up the port statuses. See Bugzilla #8190. */
mdelay(8);

/* manually resume the ports we suspended during bus_suspend() */
i = HCS_N_PORTS (ehci->hcs_params);
while (i--) {
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